SAN FRANCISCO -- Apple ( AAPL) continues to increase its share of the personal computer market, pointing to another strong quarter of sales and profit gains. In the third quarter, Apple's Mac computers accounted for 6.3% of all PCs sold, up from 5.7% a year earlier, according to estimates from IDC analysts. This growth means that Apple pulled further ahead of its competitors as it increased its lead as the No. 3 player in the market, a position it took over earlier in the year. Hewlett-Packard ( HPQ) and Dell ( DELL) remain No. 1 and No. 2. The results suggest that Apple will report another quarter of stellar revenue and profit growth on Oct. 22. The Macintosh computer has been a mainstay of Apple's business since its inception. Mac sales have stood out for their increasing contribution to Apple's sales. In the first nine months of the company's fiscal year, the Mac accounted for 41% of the company's total revenue, up from 36% during the same time last year. "I think that Apple's primary focus is and will continue to be PC," said Kirk Kim, a portfolio manager with Transamerica Investment Management. "In end, the PC game is still more profitable than the iPod or iPhone." Investors hope the popularity of the Mac's sister products--the iPod and the iPhone--will further bolster Apple's personal computer sales by highlighting the company's sleek designs and user-friendly features to a broader audience.